Bafang PAS - Riding with another person


New member
Local time
7:24 AM
Aug 21, 2018
Just a quick question for Bafang owners... The way I understand it is that the PAS levels are each set to give a fixed number of watts progressively rising from level 1 through 9. I also understand that you can use fewer levels and program you own power settings. So, how does this work to maintain safe and consistent space from other riders in a group ride? On a unassisted bike or a torque sense e-bike you just pedal a little easier or harder when necessary to keep the desired clearance but pedaling easier in PAS won't work since you still get the same motor output as long as you are pedaling. Do you stop pedaling to slow down? But then as soon as you resume you may be going too fast again. Do you shift PAS levels up and down? Seems like that might be too much of a change in most instances. Just curious. I just completed a build with a Tongsheng TSDZ2 with torque sense but am thinking of building another bike with Bafang BBSHD and want to better understand the riding dynamics.
That's why I use my throttle, almost 100% of the time, it offers the finest modulations in power levels, combined with my pedaling, and also gives me the longest range. It seems like some think using the throttle means you don't pedal at all, I go through this all the time with my buddies who ride Haibikes and other factory built bikes. We argue back and forth about it, they think they are more efficient, range wise, but in practice I don't see it. I like being able to change my assist level, via throttle, second by second, instead of pushing buttons to change the displays PAS mode. I need to ride a torque assist bike sometime, never have....
I have my PAS setup with constant power (the BBSxx can be set very differently however) with nine levels in a geometric progression (exponential). When riding with other folks and not leading, when we are on the flats it's easy enough to usually just toggle between levels infrequently to either slow down or speed up while following a safe distance - the step resolution is good for that. Often just pedaling harder or less in one level can handle maintaining pace.

If I am formation flying then throttle is the best option. Formation flying requires precision and constant fine tuning.
You guys are revealing a more global problem.

Bafang has gone to some lengths to make the result of the PAS settings what they think their customers want. For many they have succeeded. Basically it is a what I call speed mode, a kind of loose cruise control, with speed limits at each PAS level and decreasing power at higher cadence (pedal RPM). Cruise is good for the person who tends to stay at the same effort and cadence and is reluctant to row the gear shift lever, but it encourages one to stay at low cadence and you never really know how much assist you are getting.

Cruise is inappropriate and confusing for more experienced riders who know what power assist they want, need controls for setting it and like to know what they are getting. This is not just a matter of loosening up controls for the hotdogs that want higher speed and more power. Simply put, many of us want PAS settings that are straight power settings. Power mode would be much more understandable in training and more appropriate for making up a constant difference in power when riding with powerful non-e riders.

On the mechanical side speed times force equals power. On the electrical side watts equal volts times amps, so each PAS setting would be an amps setting, delivering the same amps no matter what the bicycle speed or pedal RPM.

The dream is a choice at setup of whether the PAS settings would be for speed or power, but for now the closest we can do to get power mode is to set all the PAS speed limits to 100% of the global speed limit and change the cadence level at which the power decrease starts to the highest RPM possible (Current Decay = 8). Unfortunately it is not currently possible to set the power decrease to never.
All good points that could be resolved with some creative programming of the controllers. I think the option to choose between power and speed makes good sense to me. Currently my bike a, Himiway All Terrain, each PAS level is adjustable to a percentage of what I thought was the total power available, but it seems each PAS level uses 100% power until it reaches a speed determined by the percentage set in the menu.

For example if the Max Speed is 28 Mph and you set PAS level one to 20% that turns out to be 5.6 Mph and my bike accelerates to an indicated 6 Mph in PAS level one. I would rather have the power supplied at each PAS level follow the percentage I set for that PAS level. The good thing is the throttle gives total control over the entire power range with fine adjustments available to the rider.

E-Bikes continue to evolve getting more sophisticated every month it seems. The riders of E-Bikes get more demanding with the desires of how these bikes should work as well. Some companies are better at adapting the rider requirements than others. Unfortunately these companies tend to over value their contributions to these refinements by charging ridiculous prices.
The Bafang BBS mid mount is programmable, using the correct software and connectors. I have set my PAS levels up so that the Level 1 is only 15% of available power, Level 2 is 20%, Level 3 is 25% and then gradually rising to full power specifically so I can ride with others whose bikes are not electric-assist and not be constantly stopping and starting. This has helped a lot- I can ride with kids at 15% or with my wife on her Liv Rove at about Level 5 around 50%. It does, however, require lots of Level changes because there is no torque sensor, just get used to changing the up and down buttons.
I have the Bafang BBSHD on my KHS fat bike. Most Wednesday afternoons I ride with a group of mountain bikers for a ride on some singletrack trails in a nearby provincial park. These guys are fairly fast, a couple of them have ridden their road bikes across Canada a couple times. I just set an appropriate power level, usually 3 in order to keep up. Obviously their speed varies so when they slow for hills, etc I just stop pedaling for a moment. That way I stay with the group. And I also prefer to ride last in line, mostly because I don't care to have someone closely following me.